• CSaT-191-747-765

Ion-Induced Soot Nucleation Using a New Potential for Curved Aromatics

Authors: Kimberly L. Bowal, Jacob W. Martin, Alston J. Misquitta, and Markus Kraft*

Reference: Combustion Science and Technology 191(5-6), 747-765, (2019)

  • A new intermolecular potential, curPAHIP, is developed for curved polycyclic aromatic hydrocarbons.
  • Molecular dynamics simulations show the clustering behaviour of corannulene and coronene with and without potassium ions across a range of temperatures.
  • Systems containing corannulene and ions show significant clustering compared to all others, highlighting the importance of interactions between polar curved aromatics and ions.
  • The morphologies of clusters containing curved PAHs show a "flower" motif in contrast to the "propeller" and stacked motifs of planar PAHs.

Graphical abstract A potential able to capture the properties and interactions of curved polycyclic aromatic hydrocarbons (cPAHs) was developed and used to investigate the nucleation behavior and structure of nascent soot particles. The flexoelectric charge polarization of cPAHs caused by pentagon integration was included through the introduction of off-site virtual atoms, and enhanced dispersion interaction parameters were fitted. The electric polarization and intermolecular interactions of cPAHs were accurately reproduced compared to ab initio calculations. This potential was used within molecular dynamics simulations to examine the homogeneous and heterogeneous nucleation behavior of the cPAH corannulene and planar PAH coronene across a range of temperatures relevant to combustion. The enhanced interactions between cPAHs and potassium ions resulted in significant and rapid nucleation of stable clusters compared to all other systems, highlighting their importance in soot nucleation. In addition, the resulting cPAH clusters present morphologies distinct from the stacked planar PAH clusters.

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Telephone: +44 (0)1223 762784 (Dept) 769010 (CHU)
Address: Department of Chemical Engineering and Biotechnology
University of Cambridge
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